Protect and purge your personal files
Eliminate private documents permanently from your hard drive
By Alyson Munroe
When you stop and think about it, your home computer holds a lot of information about you — credit card numbers, bank account details, passwords, medical information, web sites you’ve visited and those deep, dark secrets you share with your best friend via e-mail.
There naturally comes a time when you need to upgrade, whether it’s to a bigger hard drive or an entirely new PC. But what should you do with the old one? And what about the information on it? You need to remove this information whether you plan to donate, sell or trash your old computer.
Imagine your hard drive — including all of your personal information — falling into the wrong hands. That’s what could happen if you don’t do a little damage control before you dispose of your hard drive.
Why “delete” isn’t enough
Many people think that clearing their history, by deleting files and cookies, and emptying their computer’s recycle bin, is enough. Not so, according to Vancouver IT specialist Tony Lum. He says that’s like removing the table of contents in a book. The chapters (or your files, in this case) are still there, they’re just harder to find.
What you’ve actually done is remove a particular file from the disk’s index. The file itself still exists on your hard disk. For the average person it’s harder to recover, but an experienced programmer (or hacker) could easily locate the file. Previous or temporary versions of the file might also be saved under different names.
You need to go one step further and overwrite your data. Lum recommends you back up everything you want to keep on your hard drive and then run hard-drive wiping software, which will overwrite your information with random ones and zeros. He also recommends you use a program that overwrites your data more than once. The more it’s overwritten, the harder it is to recover.
Select software to wipe your hard drive clean
Is it impossible to retrieve your information afterward? Not 100 per cent, but Lum says unless CSIS or the CIA is after you, you should be in the clear after using one of these disk-erasing tools that are available for you to download online.
- Active @ Kill Disk: This free hard drive eraser overwrites data using zeros. You can upgrade to the professional version that conforms to U.S. Department of Defense (DoD) standards.
- Eraser: Eraser is a free download that boasts a simple user interface and top reviews from popular computing web sites and magazines.
- Softpedia/DP Wiper: Toronto IT consultant Daniel Gresser recommends freeware programs from Softpedia, such as DP Wiper, which can overwrite in 1 to 35 passes and has DoD-compliant wiping.
- WipeDrive: WipeDrive overwrites your data as many times as you like and runs a verification test.
“Always keep a record of where all important files are stored,” says Gresser, who recommends deleting each file by dropping it into DP Wiper and selecting the kind of wipe required.
To get a PC ready for sale, Gresser suggests PC users delete the following items using DP Wipe or a similar program:
- everything in the Documents folder
- all temporary Internet files
- all cookies
- all files relating to personal and financial matters that may have been stored in folders other than My Documents
- all e-mail. Outlook Express users need to search for and delete *.dbx files and Outlook users need to search for and delete *.pst files. The files will go to the recycle bin for secure deletion. Also, remember to remove all e-mail account settings and passwords, etc.
Before selling your PC, you could also take the hard drive out and keep it.
Reinstall your operating system to overwrite files
Your operating system’s installation CD should allow you to simultaneously reinstall and clear your hard drive. Lum says this technique should be enough to prevent the average person from obtaining personal information from your hard drive. However, he says he’s managed to salvage data from computers using third-party software even after an operating system was reinstalled.
Protect information on your work computer
You’ll also want to think about personal information on your work computer when it’s time to move on to a new job. You can’t wipe the hard drive since the computer isn’t your property, but you can make it somewhat harder to find sensitive information by deleting personal e-mail, clearing your web browser’s cache and history, deleting any personal files on your hard drive and emptying your trash or recycle bin.
Playing it safe
Still concerned? Don’t dispose of your hard drive. “The bottom line is, if you’re really concerned about identity theft, then don’t give away your hard drive,” says Lum.
Gresser also recommends taking some preventative measures when you set up your new computer. “One thing people can do to make disposing of PCs with sensitive data easier down the road is to encrypt their data as soon as they get a new PC or hard disk,” he says. “If strong encryption is used, then you can format the drive and dispose of it with the computer. Someone who wanted to retrieve the data would first have to undelete the data and then try to break the encryption, which is not going to happen.” He suggests using BestCrypt from Jetico to encrypt your documents.
